Putative Riemerella anatipestifer Outer Membrane Protein H Affects Virulence

Area of Science:

• Veterinary Microbiology
• Bacterial Pathogenesis
• Poultry Diseases

Background:

• Riemerella anatipestifer causes significant economic losses in poultry.
• The pathogenesis mechanisms of R. anatipestifer remain poorly understood.
• B739_0832, a conserved outer membrane protein, was previously identified as a potential diagnostic target.

Purpose of the Study:

• To investigate the role of the B739_0832 protein in Riemerella anatipestifer virulence.
• To determine if B739_0832 functions as a virulence factor in R. anatipestifer.

Main Methods:

• Construction of a B739_0832 deletion mutant (ΔB739_0832) of R. anatipestifer CH-1.
• Assessment of bacterial growth rates, duckling survival rates, and median lethal dose (LD50).
• Pathology examinations and bacterial load quantification in tissues of infected ducklings.

Main Results:

• The ΔB739_0832 mutant exhibited similar growth to the wild-type strain.
• Duckling survival rate increased to 50% with the ΔB739_0832 mutant, compared to 0% with the wild-type.
• The LD50 of the ΔB739_0832 mutant was approximately 150 times higher than the wild-type strain.
• Bacterial loads in blood and tissues were significantly lower in ducklings infected with the ΔB739_0832 mutant.

Conclusions:

• The B739_0832 protein is a significant virulence factor for Riemerella anatipestifer CH-1.
• B739_0832 contributes to R. anatipestifer's pathogenicity and infectivity in ducklings.
• Targeting B739_0832 may offer a strategy for controlling R. anatipestifer infections.